The Preservation Green Lab’s recently released report, Saving Windows, Saving Money: Evaluating the Energy Performance of Window Replacement and Retrofit, helps owners of historic homes make informed decisions about the pros and cons of retrofitting or replacing older windows in order to achieve energy savings. Researchers set out to determine the potential energy savings related to common practices for upgrading older, single-pane residential windows. Variables such as climate, regional energy costs, heating system efficiency, and window system performance were evaluated to understand which options provide the greatest energy savings for homeowners.This comprehensive and ground breaking report includes: